Stacey Dooley embeds herself on the frontline with the extraordinary all-female Yazidi battalion, who are fuelled to take revenge against the so-called Islamic State for what the UN has condemned as the \'largest mass kidnapping this century\'.As the battle to take nearby Mosul out of ISIS hands moves into its final phase in Northern Iraq, in this extraordinary film for BBC Three Stacey finds these young women\'s lives have been transformed by a desire to avenge ISIS and shows what daily life is like in these war zones.In 2014 50,000 Yazidi people fled their ancestral lands in Kurdish Northern Iraq to Mount Sinjar away from the advance of ISIS. Without food and water thousands died on the mountain and the ones left behind were massacred or captured. More than 5,000 women were taken to be used as sex slaves, with an estimated 2,000 women remain in captivity.